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authorChristoph Hellwig <hch@lst.de>2018-03-02 01:10:31 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2018-03-02 01:10:31 +0300
commit172ed391f6e40f799273e005405041b57c343cf7 (patch)
tree787b5bb07ae62d394d988aaa3333a42aa09c04ae /fs
parent5b4c845ea4f4b86c43096eb924354c83a2e26f3c (diff)
downloadlinux-172ed391f6e40f799273e005405041b57c343cf7.tar.xz
xfs: don't allocate COW blocks for zeroing holes or unwritten extents
The iomap zeroing interface is smart enough to skip zeroing holes or unwritten extents. Don't subvert this logic for reflink files. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/xfs/xfs_iomap.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 66e1edbfb2b2..4e771e0f1170 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -955,6 +955,13 @@ static inline bool imap_needs_alloc(struct inode *inode,
(IS_DAX(inode) && imap->br_state == XFS_EXT_UNWRITTEN);
}
+static inline bool needs_cow_for_zeroing(struct xfs_bmbt_irec *imap, int nimaps)
+{
+ return nimaps &&
+ imap->br_startblock != HOLESTARTBLOCK &&
+ imap->br_state != XFS_EXT_UNWRITTEN;
+}
+
static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags)
{
/*
@@ -1024,7 +1031,9 @@ xfs_file_iomap_begin(
goto out_unlock;
}
- if ((flags & (IOMAP_WRITE | IOMAP_ZERO)) && xfs_is_reflink_inode(ip)) {
+ if (xfs_is_reflink_inode(ip) &&
+ ((flags & IOMAP_WRITE) ||
+ ((flags & IOMAP_ZERO) && needs_cow_for_zeroing(&imap, nimaps)))) {
if (flags & IOMAP_DIRECT) {
/*
* A reflinked inode will result in CoW alloc.